(International) treaty

Formal agreement between states, which defines and modifies their mutual duties and obligations; used synonymously with Convention. The 1969 Vienna Convention defines a treaty as "an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments, and whatever its particular designation". Treaties create legally-binding international obligations for the States that have signed the treaty. When a national government ratifies a treaty, it becomes part of its domestic law or domestic legal order.